<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        margin: 0;
        padding: 0;
      }
      html,
      body {
        height: 100%;
        overflow: hidden;
      }
      #box {
        position: absolute;
        top: 10px;
        left: 10px;
        width: 150px;
        height: 150px;
        border-radius: 50%;
        background: rgb(0, 174, 255);
        cursor: move;
      }
    </style>
  </head>
  <body>
    <div id="box"></div>
  </body>
  <script src="./ball.js">
    let box = document.getElementById('box')
    // window.drag = new Drag()
    // drag(box)
    new Drag(box)
  </script>
</html>
